This application makes reference to, incorporates the same herein, and claims all benefits accruing under 35 U.S.C. xc2xa7119 from an application entitled RECONNECTION OF DROPPED CALL IN MOBILE COMMUNICATION SYSTEM earlier filed in the Korean Industrial Property Office on 17 Apr. 1998, and there duly assigned Serial No. 98-13789.
1. Field of the Invention
The present invention relates generally to the field of wireless communication, and more particularly, to a method of reconnecting a dropped call in a mobile communication system.
2. Description of the Related Art
In a public land mobile network (PLMN), a connection is made between a base station (BS) and a mobile station (MS) in a radio environment. In some cases, call service cannot be provided in shadow areas due to physical characteristics of the radio environment which adversely affect signal propagation. In the case where a terminal subscriber roams on foot or is moving in a vehicle, a call can be temporarily dropped. In accordance with conventional technology, if a call drop lasts for a predetermined time period, it is determined that a call service cannot be provided and the call is released. In IS-95, the predetermined time is approximately 5 seconds (i.e., equal to one frame duration 20 msxc3x97270). Upon this unintended call release, a calling party should resume the attempt to call to a called party.
To overcome the aforestated problem of call drops, several approaches have been suggested in the prior art, including:
(1) U.S. Pat. No. 5,546,382: reconnection of a circuit to continuously provide a data communication service upon generation of a transmission failure;
(2) U.S. Pat. No. 5,239,571: reconnection of an abnormally terminated communication line by adding a separate device to a terminal or modifying the terminal. That is, with the aid of a RAM in the terminal for storing information on call origination and call termination, a call is automatically set up in the case of an abnormal disconnection of a call; and
(3) U.S. Pat. No. 5,566,236: reconnection of a disconnected telephone communication by use of a nearby telecommunication system (e.g., PBX: Private Branch Exchange and Centrex: Centralized PBX Service) with the concept of an intelligent network introduced.
Accordingly, an object of the present invention is to provide a method of automatically reconnecting a dropped call which is while a call service is being provided in a mobile communication system.
Another object of the present invention is to provide a method of automatically reconnecting a dropped call while a call service is being provided in a mobile communication system.
A further object of the present invention to provide a method of manually reconnecting a dropped call which is while a call service is being provided in a mobile communication system.
It is a further object of the present invention to provide a method of reconnecting a dropped call upon detection of the call drop by a mobile station.
Another object of the present invention is to provide a method of reconnecting a dropped call upon detection of the call drop by a system (i.e., base station (BS) or mobile switching center (MSC)).
Another object of the present invention is to provide a method of reconnecting a call dropped due to an abnormality of bidirectional traffic channels for communication between a mobile station (MS) and a system, upon detection of the call drop by both the MS and the system.
A still further object of the present invention is to provide a method of reconnecting a dropped call when a mobile station (MS) detects the call drop and requests a location registration.
Briefly stated, these and other objects are accomplished by a method of reconnecting a communication link terminated by a service impediment during a service between an MS subscriber and a counterpart subscriber communicating with the MS subscriber through a mobile communication system having a plurality of MSCs connected to one another, each MSC being further connected to a plurality of base stations BSs. When the service impediment lasts for at least a predetermined first time period, the MS subscriber sends a reconnection request signal. Then, the service is reinitiated between the MS subscriber and its counterpart subscriber through one of the plurality of BSs and one of MSCs connected to the BS in response to the reconnection request signal.